Petroleum wells can be naturally flowing, injecting or can be produced by any means of artificial lift. For instance, referring to FIG. 1, a diagram of a typical sucker rod pump used as an artificial lift in oil wells is described. Well (10) may include a well bore (11) and a pump assembly (12). Pump assembly (12) may be formed by a motor (13) that supplies power to a gear box (14). Gear box (14) is operable to reduce the angular velocity produced by motor (13) and to increase the torque relative to the input of motor (13). The input of motor (13) may be used to turn crank (15) and lift counterweight (16). As crank (15) is connected to walking beam (17) via pitman arm (18), walking beam (17) may pivot and submerge plunger (19) in well bore (11) using bridle (20) connected to walking beam (18) by horse head (21). Walking beam (17) may be supported by sampson post (22).
As shown in FIGS. 1-2, well bore (11) may include casing (23) and tubing (24) extending inside casing (23). Sucker rod (25) may extend through the interior of tubing (24) to plunger (19). At the bottom of well bore (11), in oil bearing region (26), casing (23) may include perforations (27) that allow hydrocarbons and other material to enter annulus (28) between casing (23) and tubing (24). Well products may collect around pump barrel (29), which contains standing valve (30), as shown in FIGS. 3A-3B. Plunger (19) may include traveling valve (31). During the down stroke of the plunger (FIG. 3B), traveling valve (31) may be opened and product in the pump barrel (29) may be forced into the interior of tubing (24). When the pump begins its upstroke (FIG. 3A), traveling valve (31) may be closed and the material in the tubing may be forced up the tubing by the motion of plunger (19). Also, during the upstroke, standing valve (30) may be opened and material may flow from the annulus in the oil-bearing region and into the pump barrel.
The products within the well bore can include liquid and gaseous products, as well as particulates such as sand, silt, and other solids that are both naturally occurring and manmade. As hydrocarbons and water flow through the formation, these particulates are carried in the flow stream and can be carried into the production tubing, which can cause problems with the tubing and/or the artificial lifting mechanism.
With an increase in fracturing of wells designed to increase the well's production, there has been an increase in fracture sand, the most common manmade particulate found at the wellhead. Fracture sand is commonly introduced into the reservoir in an effort to create conductive channels from the reservoir rock into the wellbore, thereby allowing the hydrocarbons a much easier flow path into the tubing and up to the surface of the well.
Natural or manmade particulates can cause a multitude of producing problems for oil and gas operators. For example, in flowing wells abrasive particulates can “wash through” metals in piping, creating leaks and potentially hazardous conditions. Particulates can also fill-up and stop-up surface flow lines, vessels, and tanks. In reservoirs whereby some type of artificial lift is required such as rod pumping, electric submersible pumps, progressive cavity, and other methods, production of particulates can reduce the life of the down-hole assembly and/or increase maintenance costs.